Fix NPE in WaitStrategy used for test containers

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/testcontainers/CassandraContainer.java

@@ -44,7 +44,7 @@ public class CassandraContainer extends Container {
 	private static class WaitStrategy extends HostPortWaitStrategy {
 
 		@Override
-		protected void waitUntilReady() {
+		public void waitUntilReady(GenericContainer container) {
 			super.waitUntilReady();
 
 			try {
@@ -59,7 +59,7 @@ public class CassandraContainer extends Container {
 		private Callable<Boolean> checkConnection() {
 			return () -> {
 				try (Cluster cluster = Cluster.builder()
-						.withPort(this.container.getMappedPort(PORT))
+						.withPort(container.getMappedPort(PORT))
 						.addContactPoint("localhost").build()) {
 					cluster.connect();
 					return true;

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/testcontainers/Neo4jContainer.java

@@ -42,10 +42,10 @@ public class Neo4jContainer extends Container {
 	private static class WaitStrategy extends HostPortWaitStrategy {
 
 		@Override
-		protected void waitUntilReady() {
+		public void waitUntilReady(GenericContainer container) {
 			super.waitUntilReady();
 			Configuration configuration = new Configuration.Builder()
-					.uri("bolt://localhost:" + this.container.getMappedPort(7687))
+					.uri("bolt://localhost:" + container.getMappedPort(7687))
 					.build();
 			SessionFactory sessionFactory = new SessionFactory(configuration,
 					"org.springframework.boot.test.autoconfigure.data.neo4j");